You make a full payment, but because you owe them a late charge, or any one of their other "extra" fees, they do not credit your payment to your account. Rather they put it in a "suspense" account. Next month you pay the full payment again and they also put your payment in the "suspense" account. Now you owe them only ~$150 in reality, but since all your money is in the suspense account, they say you are 2 months in arrears and they foreclose on you. You will never see the money in the "suspense" account. It all goes into "legal" and other "fees".
This is a hideous bank that never answers the phone promptly, tells you they want to help, and after you fill out copious forms, they tell you sorry - can't help.
Indymac Bank deserves to go out of business. Their management deserves to go to some more despicable place.